Tyre Warmer repairs?

[out_in_front]

My Tyre Warmers have a bit of an issue - they keep reading 43ish deg and therefore continue to heat the tyres to some bullshit amount of temperature! I figure either the temp sensors are gone or something has gone wrong in the controller - Anyone here have experience fixing them?

If not I will probably end up buying some new ones I suppose...

[Crobbo]

Are they reading 43 the whole time even when cold?

Can you see where the probe is?

[Nero Diablo]

There is a thread on this but it was more about the chicanes which the connections used to break.

[robwas]

PM Apatheticend he used to repair alot of them

[out_in_front]

Ok so he is not replying - I had better order a new set before so they can get here on time before next weekend -
Saw both of these for pretty cheap prices, has anyone had experience with either? I want to order some today so that hopefully they will be here in time (both within australia so I am assuming they will take longer than from teh states... )

Jobiez Sportsbike Products - TYRE WARMERS

Emtek Racing Accessories - Analog Tyre Warmers

[g0zer]

they keep reading 43ish deg and therefore continue to heat the tyres to some bullshit amount of temperature! I figure either the temp sensors are gone or something has gone wrong in the controller

thermocouple (temp sensor), the controller or the wiring inbetween the two. first thing is check continuity in the wiring. a. thats the only thing thats easy to fix and b. is the most probable cause of the problem anyway.

what do you mean "43ish"? does it ever change? if its frozen, the controller input channel input signal range may be bounded. depending on how its been configured it (bounded input range) if the input signal is lost, it can result in the last known sensible reading being displayed.

(like when pedrosa's rear wheel speed encoder cable was busted, that system would have been configured with a bounded input range, but if the input signal is lost rather than making the last sensible reading retentive (which would cause the traction control to kill power to rear wheel as soon as the expected rear wheel speed exceeds the last sensible reading) they chose to cause it to fail high which then disables traction control. maybe it would have been better for pedrosa if it had been configured to trigger a limp home mode upon signal loss rather than risk high siding the rider).

also, a configuration for heating loop should be fail high to protect from fire risk in event of signal loss.

safety first

[out_in_front]

Yeah checked all the wiring, so thats not the problem, and considering both readings went at the same time (two warmers with a single controller box) I figure the problem is inside the controller box - there is no visible damage to the circuits either, so the problem is probably one of the components inside the controller being burnt out etc.

[g0zer]

oh right, yeah sounds like it (controller failure). but its a curious mode of failure for both channels to drop out at same time. if the channels are powered then the power to the channels could have dropped out and being a cheap controller no DC power failure interlock on the output channels (again to protect from fire caused by outputs energised forever if input is lost).

edit: if you drop setpoint below 43C do the outputs de-energise?

[Sean'o]

These guys repair warmers Sportsbike - Motorcycle Parts & Accessories; Tyre Warmers, Tire Warmers. Motorcycle wheels, Brake systems, Slipper clutches, Rear sets, Fuel tank caps, Bike stands, Radiator Guards. Motorcycle Performance Accessories sent World Wide. but not sure about the controller box which is where your problem seems to lay. The emtek ones you listed are being used by a few guys at the track without any issues so far, they seem to be good value for money compared to some of the other cheap shit out there.

[out_in_front]

Yep - heard the swiches go when they dropped below 43 (I am at home so I can try any other suggestions)
Also worth noting that they are always reading that 43ish deg - even on startup when they should be reading lower than that.

[g0zer]

sounds like the brain is working then, just the input channels that arent. since its both channels at same time that narrows down the troubleshooting effort to circuitry that is common to both channels (ie: their power source). if you really wanted to you could open the brain, trace back from the input channels to identify the DC power source, check if its still functioning and if so hope for a break that you can bridge.

Power Supplies in Temperature Measurement
Power supplies are an important part of a successful temperature loop. A steady and reliable 24 V DC is required for all the other
components to work correctly.

http://phoenixcontact.custhelp.com/ci/fattach/get/20942/

or

Working with Thermistors and RTDs - National Instruments

Working with Thermistors and RTDs

[out_in_front]

From what it seems to me - these arent DC warmers... the power comes in and the one wire goes straight to the warmer elements. The other end of the loop goes through the switches. I cant see any obvious rectifier circuit in there either.

Yep - did a bit of electrical engineering at uni, not afraid of things getting a bit more advanced than this, although I am sure I will hit my limit soon!

Just experimenting to see if the switch reset sorts anything out, after that I will open the box and post up some photos of the guts of it if that will help.

[out_in_front]

Ok here are the pics:




- - - Updated - - -

The blue and brown wires at the top are the power in,

One loop goes directly to the warmers, the otehr is controlled by the two black switches

The transformer drops the voltage down to 25V - I figure that the little balck things on the bottom of the circuit board might actually be diodes, and therefore form a rectifier so the control side of the circuit could well be 24VDC

Green and red wires are the input from the thermocouples
Blue and black are the power to the heating elements.

[g0zer]

From what it seems to me - these arent DC warmers... the power comes in and the one wire goes straight to the warmer elements. The other end of the loop goes through the switches. I cant see any obvious rectifier circuit in there either.

eh? the elements wont be DC.

when its a umm brain based system, im used to seeing thermocouple/RTD transmitter wired to an analog input channel, the brain compares that channel to the setpoint and decides what to do about it (whether the output channel to the heaters should be closed or not). in the case of AC elements there would need to be a relay to step the brains LV DC output up to 240VAC for the elements... is that the switches you are talking about?

[Crobbo]

Must be a supply for the temp probes though.

This seems remarkably similar to a problem we have on industrial dryers if there is an over temp a safety will trip on the temp probes and they display 29 degrees.